Formulating cold tone paper developers

Photo Engineer · Apr 14, 2009

Thiourea is banned in some states in the US. Interestingly enough in some of those states, it is found as a natural product in many common wildflowers. The toxicity of thiourea has been under debate for quite a while and nothing seems to be done. I think that it is due to the fact that the results are not conclusive enough.

PE

Kirk Keyes · Apr 14, 2009

And it's been traditionally used in silver polish too. That said, chemical safety sources list it as a possible carcinogen.

Ian Grant · Apr 15, 2009

Kirk Keyes said:
The benzotriazole variation of Ansco 130 that I mentioned above certainly does change the tone of Ilford Warmtone FB paper, and much as you show in your scans above. No thiourea needed to make a nearly neutral paper considering how warm it is to start with.

Could you take some color densitometer readings of some paper in your formula at Dmax and compare them to the same paper in regular developer so we can get an idea of the color shift?

Unfortunately I have no access to a Densitometer, there's never been a tradition of photographers using them in the UK, outside professional colour labs.

The shift we are looking for is past Neutral to a Blue black tone, Thiourea appears to be capable of doing this but there are organic alternatives.

The work on Thiourea to give blue/black tones was by a British Photo-chemist C.E.K. Mees of Wratten & Wainwright, Kodak bought the company and he moved to the US to set up Kodak's Rochester Resarch Laboratories.

Ian

Kirk Keyes · Apr 15, 2009

Ian - If you want to send me some samples/step wedges, I'll read them and post results. Then we can compare with my modified Ansco 130 developer. PM me and I'll give you my address.

By the way, I don't know why more people don't use color densitomety so they can better discuss these matters...

Photo Engineer · Apr 15, 2009

Densitometry is useless unless it is comparative densitometry with a check and the experiment!

PE

Kirk Keyes · Apr 15, 2009

That's what I plan on!

schlger · Apr 17, 2009

Phenyl Mercaptotetrazol in about 5-10 mg / l conc. of PQ gives a definite bluer tint than benzotriazole. It also makes the blacks a bit deper. I found out, that Forte Fortezo reacted with pepper grain with amounts over 8 mg/l conc. Nitrobenzimidazole is another agent, that makes the tone bluer.
I bought my Phenylmercaptotetrazol at Organica in Wolfen, Germany.

Best regards
Gerhard

Kirk Keyes · Apr 17, 2009

The Photographers Formulary had 1-phenyl-5-mercaptotetrazol last year. A percent solution, 100 ml bottle is what I bought. It was pretty inexpensive. I suspect they still have it. Email them and ask, as I can't find it on the web site.

Photo Engineer · Apr 17, 2009

Still there.

http://www.photoformulary.com/DesktopDefault.aspx?tabindex=2&tabid=9&CategoryID=101&langID=0

PE

Tom Kershaw · Apr 17, 2009

I have mixed up a developer containing Potassium Iodide instead of Benzotriazole and will report back.

Metol 4g, Sodium Sulphite 25g, Hydroquinone 12g, Sodium Carbonate 65g, Potassium Iodide 16g, water to make 1000ml.

I intend to dilute 1+3 for the working solution to get in the middle of the Potassium Iodide content range suggested by Ian Grant.

Tom.

Photo Engineer · Apr 17, 2009

KI at that level is going to be interesting to hear about. Please keep us posted.

PE

Tom Kershaw · Apr 18, 2009

Initial impressions of Potassium Iodide

Photo Engineer said:
KI at that level is going to be interesting to hear about. Please keep us posted.

PE

PE,

Your statement was well chosen. At the dilution used (4g KI per litre of working solution) only a faint image appeared on ILFORD Galerie and no image on Slavich Unibrom.

Switching to Kentmere Bromide: Mixing up a fresh developer with no restrainer and then adding 50ml of the initial KI containing developer did seem to produce a blue "tone" along with extensive yellow staining. However, after approximately four minutes in the fixer, both the blue "tone" and the yellow stain had vanished. Tonality and density on the final print(s) are fine but there is little evidence of attempts to produce cold tones.

The addition of a further 100ml of the KI containing developer to the working solution significantly retarded development and produced a mottling effect.

Tom.

Photo Engineer · Apr 18, 2009

KI should be used sparingly in the developer with paper emulsions. They can "tone" the image, but will retard development significantly. Toning in this sense, to make warm toned papers, is best done in the emulsion making process or by adding toning pigments to the paper support or both.

PE

schlger · Apr 20, 2009

schlger said:
Phenyl Mercaptotetrazol in about 5-10 mg / l conc. of PQ gives a definite bluer tint than benzotriazole. It also makes the blacks a bit deper. I found out, that Forte Fortezo reacted with pepper grain with amounts over 8 mg/l conc. Nitrobenzimidazole is another agent, that makes the tone bluer.
I bought my Phenylmercaptotetrazol at Organica in Wolfen, Germany.

Best regards
Gerhard

I forgot to add, that the Phenyl Mercapto Tetrazole solution has a concentration of 1g in 1 liter of destilled water with a pinch of soda (0,8g) for better solubility.

sun of sand · Apr 20, 2009

Phenyl Mercaptotetrazol sounds like it does what people have said thiocyanates will do
I in my own goofy way added some pot. thiocyanate to 103 and got quite purplish blue tones but also lower contrast
maybe just too much
probably needs measured in grains per liter

Photo Engineer · Apr 20, 2009

PMT and Thiocyanate are at the opposite end of the spectrum in terms of what they do. PMT forms a more insoluable silver salt and gives you less speed and development, but SCN forms a more soluable salt giving solvation effects, and lower contrast. They both change tone. Their useful range in developers are vastly different, PMT being used in the mg range and SCN being used in the gram range.

PE

Tom Kershaw · Apr 20, 2009

In reference to the discontinued Harman Cooltone product, I take it the presence of a proprietary restrainer would lend the greatest influence in producing blue-black tones even on papers such as Kentmere Kentona?

Tom.

Photo Engineer · Apr 20, 2009

Tom;

Generally, the toning agent in the emulsion formula will overwhelm (or tend to overwhelm) any effects of tone adjustment possible by the addenda in the developer. The first word in the previous sentence is most important! It is difficult to predict, not knowing the formula.

Sometimes, just the method of precipitation will significantly alter an emulsion formula all else being equal. I have seen a formula in which everything is the same except for the order of addition, but that order changes the tone of the image with no change in developer or addenda.

PE

Bertil · May 3, 2009

Harman Cooltone was really something! After Mike Crawfords article in BW Photography I tried the new Harman Warm- and Cooltone developers, I was delighted! These two, and in combination, and together with Ilford MG Warmtone and Forte Polywarmtone was excellent and quite enough for me - need nothing more!! But the very best things in may years: Harman Cooltone and Polywarmtone sadly disappeared.
Now the POLYWARMTONE PROJECT has started !!! (http://www.polywarmton.com/English/register.php), time to start the HARMAN COOLTONE PROJECT??? (-- at least a working formula!)
//Bertil

ronlamarsh · May 4, 2009

cooltones

Anscojohn said:
Not being a chemist nor even scientifically minded, I go with what is told to me by the experts and with my own experience.

Real cold tone is, first and foremost, in the paper itself. That being said, I FEEL that the significant increase in metol in Ansco 103, compared to say, D-72, is an help in producing colder tones. That, plus the limiting of bromide in the stock solution to just enough to keep print tone fairly constant--rather than preventing fog. I leave it to the benzotriazole to limit fog and to help produce a colder tone. I was told not to eliminate the bromide completely, as bromide is produced as a by-product of the developing process, and that a small amount of bromide to begin with helps maintain more constant print tone.
I agree with Ian that too much benzo is not a good thing; and that adding it to the working solution is a good way to get fairly precise control of print tone.
So--if'n ya wantz cold tones; use a cold tone paper--but the developers can help if bromide is kept to a minimum.

I think John is right, if your paper has a warmer base you will be fighting a losing battle. I use EDU. Ultra(foma) paper which is decidely warm. Comparing the paper base to Ilford you can see it is not as white. That said I have found a way to cool it off to my liking: I develope in a coldtone developer i.e. ansco 103 or one of many similiar formulas diluted 4:1(increases exposure time)with about 10ml of 1% BZT added per liter of working solution then tone in selenium 20:1 for 4mins. This comes real close to prints with ilford MGVI but I find the foma paper has a more pleasing tonal scale TO MY EYE(caps because all things are relative). My eye is no better than anyone elses just different. Another advantage of the foma paper is that if you want really beautiful warm tones you can develop in Ethol LPD 2:1.

Formulating cold tone paper developers

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